A global brightness-variation compensation (GBC) scheme is proposed to improve the coding efficiency for video scenes that contain global brightness-variations caused by fade in/out, camera-iris adjustment, flicker, illumination change, and so on. In this scheme, a set of two brightness-variation parameters, which represent multiplier and offset components of the brightness-variation in the whole frame, is estimated. The brightness-variation is then compensated using the parameters. We also propose a method to apply the GBC scheme to component signals for video coding. Furthermore, a block-by-block on/off control method for GBC is introduced to improve the coding performance even for scenes including local variations in brightness caused by camera flashes, spotlights, and the like. Simulation results show that the proposed GBC scheme with the on/off control method improves the peak signal-to-noise ratio (PSNR) by 2-4 dB when the coded scenes contain brightness-variations.

A novel head-tracking technique for a full-color stereoscopic video display system is presented. Using this head-tracking system, the stereoscopic area is increased by a factor of three and stabilized stereoscopic images are observed. Two kinds of large-size rear-projection stereoscopic display systems that do not require special glasses are proposed. Experimental tests, confirming the effectiveness of the proposed systems, are described. By incorporating these techniques into visual communication systems, such as TV telephone systems, video conference systems, or virtual reality systems, a very natural and accurate depth sensation which cannot be obtained by conventional systems that require the viewer to wear special glasses may be possible.>